Dust collecting system in a coal charging operation for coke ovens

ABSTRACT

This invention is a dust collecting system for gases containing dust produced in the case of charging coke ovens with coal wherein a plurality of divided sub-ducts are arranged on coke ovens and a main duct connected with them is connected with a dust removing apparatus so that a discharged gas having passed through a dust collecting and removing apparatus for gases containing dust as provided in a coal charging car may be completely introduced into the duct, may have dust well removed with the dust removing apparatus connected with the main duct and may be discharged into the atmosphere as a very clean gas.

Ilnited States Patent Ikeda et a1.

DUST COLLECTING SYSTEM IN A COAL CHARGING OPERATION FOR COKE OVENSInventors: Minoru lkeda; Masatsume Sugimoto, both of Wakayamashi, JapanSumikin Coke Company Limited, Wakayamashi, Japan Filed: Nov. 4, 1971Appl. No.1 195,629

Assignee:

Foreign Application Priority Data Nov. 4, 1970 Japan 45/109420 US. Cl202/263, 214/18 PH, 214/35 R, 55/385, 55/315, 55/233 Int. Cl C10b 27/04Field of Search 202/262, 263; 214/18 PH, 35 R; 55/385, 231, 233, 315

References Cited UNITED STATES PATENTS 3/1972 Palumbo 202/263PRE-CLEANER T COLLE TING HOODS Primary ExaminerNorman Yudkoff AssistantExaminer-David Edwards AttorneyNeil F. Markva et al.

[57] ABSTRACT This invention is a dust collecting system for gasescontaining dust produced in the case of charging coke ovens with coalwherein a plurality of divided subducts are arranged on coke ovens and amain duct connected with them is connected with a dust removingapparatus so that a discharged gas having passed through a dustcollecting and removing apparatus for gases containing dust as providedin a coal charging car may be completely introduced into the duct, mayhave dust well removed with the dust removing apparatus connected withthe main duct and may be discharged into the atmosphere as a very cleangas.

5 Claims, 5 Drawing Figures SUCTION MEANS DUST COLLECTING HOODSTATIONARY DUST REMOVER INVENTOR fl/m/o/w [mam mz' PATENIEU DU 23 I975SHEET 30F 5 PATENIEDUBI 23 1975 3. 767536 SHEET u 0? 5 FIG 4PATENTEDUBIZLHBH 3,767,586

SHEET 5 CF 5 4 INVENTORS /fE/M U (15 DUST COLLECTING SYSTEM IN A COALCHARGING OPERATION FOR COKE OVENS This invention relats to a dustcollecting system for gases containing a large amount of dust anddischarged into the atmosphere through a charging port.

For this kind of system, there are already known Japanese patentpublications Nos. 16,669 and 30,101/1971.

The above mentioned two publications relate to a dust collecting andcleaning system wherein a coal dust flowing duct in a coal charging caris made free to connect with a gas and dust collecting pipe fixed on anoven and a dust removing apparatus is connected with the pipe at one endor an atmosphere pollution preventing apparatus wherein a guide carand/or coal charging car is provided with a mechanism for introducingdust gases produced in a coke producing process outside a coke oven sothat a dust gas may be introduced to connectrate and collect dust. Theyshow a system wherein, by using an introducing mechanism fitted to acharging car, a dust-containing gas produced in the case of chargingcoke ovens with coal is introduced into a dust arranged on or outsidecoke ovens and are led to the end part of the duct to remove dust.

However, when an introducing mechanism fitted to a charging car as inthe above mentioned patent publications is connected with a ductarranged on a coke oven, the atmosphere from many other connecting ports(though closed with valves, needless to say) provided in said duct willleak in. Therefore, even if the leakage through one suction portisslight, in a coke oven having more than a hundred connecting ports,the total leakage will be so large that it will be very difficult tocompletely introduce dust gases into the duct arranged on the oven.

An object of the present invention is to provide a system for completelyintroducing such dust-containing gases into a duct provided on a cokeoven wherein a plurality of divided sub-ducts are arranged on coke ovenswhich are connected with a main duct through respective valves and adust remover is provided in the end part of the main duct so that onlythe sub-duct into which a dust-containing gas is being introduced may beconnected with the main duct but the other sub-ducts may be interruptedfromthe rnain duct by closing the valves, therefore the atmosphereleaking the through the connecting port may be reduced to be a fractionand the dust-containing gas may be introduced into the sub-duct veryeasily and completely.

Further, in the above mentioned patent publications, by using adust-containing gas introducing mechanism fitted to a charging car, adust-containing gas produced at the time of charging a coke oven withcoal is introduced and sucked into a duct arranged on or outside theoven, is led into a dust remover provided in the end part of the ductand is cleaned. However, such large amount of coal gas is present asmixed in the dustcontaining gas produced at the time of charging theoven with coal that a flame inside or outside the coke oven has a greatdanger of causing on explosion of the gas in the course from thedust-containing gas introducing mechanism fitted to the charging car tothe dust remover through the duct as often experienced also by theinventors.

According to the present invention, in the case of introducing adust-containing gas into a duct arranged on an oven by using adust-containing gas introducing mechanism fitted to a coal charging car,the dustcontaining gas in which coal gas is present as mixed is burnedin advance so as to be converted to an inert gas and at the same timethe dust is pre-washed and the gas is cooled so that the gas explsionmay be positively prevented and the discharge of the gas and removal ofthe dust may be easy.

In a coke oven, in the case of a coal charging operation by using a coalcharging car, when coal is dropped into a coke oven chamber through acharging port at the oven top in order to charge the coke oven with thecoal, hot air on the coal within the oven chamber will be quickly drivenout of the coke and at the same time coal gas will be severely producedfrom a part of the coal quickly subjected to the heat influence of theoven chamber wall kept at a high temperature of about 1,000 C.

Such hot air and coal gas are accompanied with such large amount of coaldust of the coal charge that they will diffuse around as a black orbrown jetted smoke through the top of an open rising pipe or thecharging port during the charging with the coal to remarkably pollutenot only the working environment but also the general environment.

As regards such gas accompanied with dust as is jetted out through therising pipe, there is carried out a means of sucking and introducinginto a gas collecting main pipe a part of a dust-containing gas producedwithin an oven chamber by a sucking action caused by jetting a highpressure steam or high pressure water in the bent part of the risingpipe for the connection with the gas collecting main pipe by cosing thetop of the rising pipe and opening a valve between the rising pipe andthe gas collecting main pipe at the time of charging with coal. However,the volume of the gas which can be sucked and introduced into the gascollecting main pipe is about 30 to 20 percent of the dust-containinggas produced within the oven chamber and the greater part of the gas isjetted and diffused into the atmosphere through the charging port at thetop of the coke oven.

There is worked a method for collecting a dustcontaining gas jetted outthrough a charging port and diffused into the atmosphere and removingthe dust wherein a coal charging car is provided with a dust collectingapparatus and the coal charging port through which the dust-containinggas is jetted out during the coal charging operation is covered with adust collecting hood so that the dust-containing gas may be led into thedust collector to remove the dust. However, the dust content in thecollected dust-containing gas is so high as to be 15 to 30 g./Nm that,even if the dust is removed at an efficiency of percent with the dustcollector, 2 to 3 g./Nm of the dust will still remain in the exhaust gasafter the dust is removed and the exhaust gas after the dust is removedas discharged into the atmosphere out of the dust collector fitted tothe coal charging car is still a black or brown exhaust smoke. Thus, thedust collector set in the coal charging car is restricted in thecapacity and performance by the dimensions or weight in theinstallation, it is unreasonable to expect a great improvement in thedust removing and collecting efficiency and it is very difficult tocompletely collect the dust. Through the dust collecting hood coveringthe charging port, a large volume of the dust-containing gas not yetcollected in the dustcollecting apparatus leaks out and is dissipatedinto the atmosphere.

Further, in this dust-containing gas, unrefined coal gas produced by thethermodecomposition of coal is present as mixed and the gas compositionconcentration always varies in a wide range. Therefore, such gas will beignited from the fire source within the coke oven chamber and theexplosion of the gas will frequently occur within the dust collectingapparatus. This is a grave problem in the safety of the operation. Aperfect dust collecting apparatus having no gas explosion and high inthe efficiency of collecting and removing dust has been hoped for.

An object of the present invention is to provide a dust collectingsystem for dust-containing gases jetted out through a coal charging portat the top of a coke oven chamber in a coal charging operation by usinga coal charging car in a coke oven so that the danger of the explosionof the gas within the dust collecting apparatus may be positivelyprevented and the dustcontaining gas may be substantially completelycollected and efficiently removed. That is to say, while thedust-containing gas jetted out through the coal charging port is beingjegnited and burned with an jgniting and burning device provided near adust collecting hood provided in the lower part of a coal hopper of thecoal charging car or near a duct following the dust collecting hood, itis sucked into the dust collecting hood together with a comparativelylarge volume of air with an exhauster provided in the coal charging car,is thus made an inert gas composition very stable against explosion, isthen cooled and has coarser particles of the dust separated with aprecleaner provided with a water jetting device and a rotating metalscreen in the course of the pipe line from the dust collecting hood tothe exhauster and is then passed through the exhauster. In such case, anexhauster of a type which is also a dust remover may well be used.

The dust-containing gas having left the exhauster is led to a sub-ductarranged on the oven through an exhaust duct.

On the other hand, a plurality of divided sub-ducts are arranged assectioned respectively for a battery of about to 30 oven chambers. Eachsub-duct is provided with a corresponding suction port for each ovenchamber. Each suction port is provided with a value. The sub-duct isconnected with the main duct through the valve. A dust collector havinga sufficient capacity and dust removing performance and an exhauster areconnected with the main duct in the end part. A connector is fitted inthe end part of an exhaust duct connected with the outlet of theexhauster provided in the coal charging car so as to be connected withthe suction port of the sub-duct corresponding to the oven chamber whichis being charged with coal to open the value of the suction port.Therefore, the dust-containing exhaust gas is sucked into the sub-ductfrom the exhaust duct of the coal charging car, is further led into thedust remover through the main duct, has the dust removed and isdischarged into the atmosphere through the exhauster.

According to the dust collecting system of this invention, not only theexplosion of the gas within the dust collecting apparatus oftenexperienced in the case of collecting dust in the coal chargingoperation can be positively prevented but also the dust-containing gascan have dust collected and removed substantially completely and farbetter than with the dust collecting apparatus set in the coal chargingcar. Further, the exhaust gas can be discharged into the atmosphere as aclean gas in which no tarry substance is recognized at all and thereforethe environment pollution problem caused by the dust-containing gasproduced in the coal charging operation can be substantially solved.

In the drawings:

FIG. 1 is a general elevation of a dust collecting system according tothe present invention showing a coke oven in section;

FIG. 2 is an elevation of a dust collection hood provided in a coalcharging car, pre-cleaner, exhauster and arrangement of connecting themshowing a sub-duct and main duct in section;

FIG. 3 is a plan view of a dust collecting exhaust duct of the coalcharging car, sub-duct arranged on the oven and main duct;

FIG. 4 is an elevation of a device for connecting the sub-duct with thedust collecting exhaust duct provided in the coal charging car.;

FIG. 5 is a block diagram of the operation of the value interposedbetween the sub-duct and main duct.

The numeral 1 is a coke oven battery consisting of 106 ovens, each ovenchamber being of a length of 5,560 mm. height of 6,000 mm. and width of450 mm. and about 27 tons of coal being put into each oven through fourcharging ports 2. A coal charging car 4 is arranged at the oven top 3 soas to be movable on the oven top. Said coal charging car 4 is providedwith as many as 4 coal hoppers 5 as the charging ports. In the lowerpart of the coal hopper 5 are a coal feeder to drop coal into thecharging port 2 and a dust collecting hood 6 to cover a coal feedingport 7 and charging port 2. The dust collecting hood 6 is of a sizesufficient to cover the charging port 2 and has an igniting device 8provided with an electric igniter and oil burner to expand a flamewithin the dust collecting hood. A duct 9 extends from the dustcollecting hood 6 so as to be connected with a pre-cleaner 10 which isof a diameter of about 1000 mm. and within which a metal screen 11 ofcomparatively large meshes rotates so that water may be jetted onto thismetal screen through a nozzle 12. The outlet of the pre-cleaner isconnected with an exhauster 14 through a duct. This exhauster has a windvolume of 500 m. /min. and can perfectly prevent dustcontaining gasesfrom escaping into the atmosphere through the charging port and dustcollecting cover.

The exhauster 14 may be also a dust remover.

An exhaust duct 15 is connected with the outlet of the exhauster 14 andhas a connector 16 at the end. This connector 16 advances or retreats bysliding at the end of the exhaust duct 15 by the operation of a fluidcylinder 17. When the coal charging car 4 moves, the connector 16 willretreat to be separated from a suction port 19 of a sub-duct 18 providedto correspond to each oven chamber of the coke oven and having a valve20. Said sub-duct 18 is arranged along the oven battery on the coke ovenand is usually divided into a plurality by being sectioned for 10 to 30suction ports. This is very important to effectively sucking the dustcollecting exhaust of the coal charging car.

In charging the coke oven with coal, when the connector 16 is advancedto be pushed against the suction port 19, a projecting metal piece 21 ofthe connector 16 will push the valve 20 open. The cross-sectional areaof the sub-duct 18 is 1.0 m. Each of the plurality of the dividedsub-ducts is connected with a main duct 23 through a valve 22. The mainduct 23 is connected at the end with a dust remover 24 set on theground. The outlet of the dust remover 24 is opened to the atmospherethrough an exhauster 25 which has a wind volume of 1,500 mP/min.

The operation shall be explained in the following. When the coalcharging car loaded with coal moves to be above the coke oven chamber tobe charged with coal, theexhauster l4 and pre-cleaner of the coalcharging car will be started the metal screen 1 1 will rotate and a pump26 will jet water in a water tank 27 onto the metal screen 11 throughthe nozzle 12. Then the dust collecting hood 6 will be lowered to coverthe coal charging port 2. The burner of the igniting device 8 will beignited and a flame will be blown into the dust collecting hood.

On the other hand, the exhauster 25 will be started in advance. When thefluid cylinder 17 is operated to advance the connector 16 into contactwith the suction port 19, the projecting metal piece 21 will push thevalve 20 open so that the exhaust duct and sub-duct 18 may communicatewith each other.

At the same time, a pushing plate 36 will push a switch L fitted to thesuction port belonging to the subduct 18 to close its electric contact,therefore an electric current will pass through a relay R in FIG. 5,thereby electric contacts R and R -l will close, R -2 andR -3 will open,therefore the electric current will be interrupted in relays R and R andcontacts R -0 and R -0 to feed electric currents to electromagneticvalves 31 and 32 will open. Therefore, when the electric contact R -0closes, an electromagnetic valve 30 will operate to push down the valvebody and a fluid cylinder 33 to be fed with a pressure fluid (forexample, compressed air) 37 will operate in the direction of opening thevalve 22 interposed between the sub-duct l8 and main duct 23 so that thesub-duct 18 and main duct 23 may communicate with each other. When theelectric contacts R -0 and R 4) are open, the valve bodies of theelectromagnetic valves 31 and 32 will be pushed up by springs and fluidcylinders 34 and 35 to be fed with the pressure fluid 37 will operate inthe direction of closing valves 22 and 22", respectively, interposedbetween sub-ducts l8 and 18" and the main duct 23 so that thecommunication between the subducts l8 and 18" and main duct 23 may beinterrupted.

Therefore, as the valves 22' and 22" interrupt the communication withthe main duct 23, the other subducts l8 and 18" than the sub-duct towhich belongs the suction port with which the exhaust duct of the coalcharging car is in contact will not impede the suction of the dustcollecting exhaust by the coal charging car with the leakage of airthrough many suction ports belonging to the sub-ducts 18 and 18".Further, even if there is any leakage of air through the other suctionports provided in the sub-duct 18 to which belongs the suction port withwhich the exhaust duct of the coal 7 charging car is in contact, as thenumber of the other suction ports is such as will not impede the suctionof the dust collecting exhaust by the coal charging car, there will beno problem, needless to say.

For example, when an undivided continuous duct is arranged on the cokeoven consisting of 100 ovens, suction ports corresponding to therespective oven chambers are made in this duct, the duct is connectedfor suction at one end with an exhauster of a wind volume of 1,500mflmin. and the size of the suction port is l m. X 1 m. 1 m.*, the valveof the suction port will be required to be easy to open and close andvery sim ple in the structure. Therefore, in such valve, a clearancewill be necessarily produced between the valve body and the pipe wall inmaking the valve. If there is a clearance of 5 mm. and air leaks inthrough it at a velocity of 10 m./sec., the volume of air flowing intothis duct will be 1 m. X 4 sides X 0.005 m X 10 m./sec. X 60 sec. X 100-I 1,200 m. /min.

It will be impossible to suck and introduce 500 mF/min. of the dustcollecting exhaust of the coal charging car into the duct.

On the other hand, if a continuous subduct is provided with 20 suctionports and consists of five subducts, the volume of air leaking into thesub-duct will be 1 m. X 4 sides 0.005 m. X 10 m./sec.X 60 sec. X (20 4)240 m. /min.

Thus the dust collecting exhaust of the coal charging car will be ableto be completely sucked and introduced into the duct.

When the preparation for collecting dust is made as in the above, thecoal feeder of the coal hopper in the coal charging car will be operatedso that coal may be put into the oven chamber through the four chargingports 2 at the top of the coke oven chamber. Thus the dust-containinggas jetted out through the charging ports will be caught by the dustcollecting hood 6, will be burned by the flame of the burner 8 so thatthe tarry substance and other combustible compositions may besubstantially burned, will be led to the prewleaner 10 through the duct9 and will be cooled therein with water jetted out through the nozzle12. Coarser particles of dust will be caught by the mesh screen 11. Thedust will be shaken around by the rotation of the mesh screen, willcollect together with washing water in the lower part of the casing andwill accumulate in a dirty water tank 28. The water containing dust inthe dirty water tank will be discharged with a separate automatic devicewhile the coal hopper in the coal charging car is being loaded with coalwhen the coal charging operation is finished and, at the same time, awater tank 27 will be fed with fresh water. In the pre-cleaner, aboutpercent of the dust accompanying the gas will be removed.

Table 1 is of the results of measuring the dust removing exhaust gas ofthe coal charging car equipped with the pre-cleaner wherein the volumeof sucked wind was then 250 mP/min. but was improved later to be 500 m./min.

TABLE 1; DUST CONTENTS The gas having left the pre-cleaner will come outto the exhaust duct through the exhauster 14. As the coarser particlesof the dust have been mostly removed in the pre-cleaner, it will be verylittle to damage the blades of the exhauster. And yet the gas havingleft the pre-cleaner can not be discharged as it is into the atmosphere,because a small amount of dust will still remain in the gas.

The exhaust gas having left the exhaust duct 15 will enter the sub-duct18 as it is, will be led into the main duct 23 through the valve 22,will have dust removed in the wet-type dust remover 24, will become aclean gas and will be discharged into the atmosphere through theexhauster 25.

Table 2 is of the results of measuring the dust removing exhaust gas ofthe dust remover 24 wherein, as the dust content is less than 0.1 g./Nm.and the tarry substance in the gas has been already burnt out, the dustremoving exhaust gas is so clean as to have substantially no influenceon the pollution of the atmosphere.

We claim:

1. In a coke oven system comprising a battery of coke ovens arranged ina longitudinal direction, each oven having at least one coal chargingport, and a coke charging car adapted to travel along a path in saidlongitudinal direction to a plurality of stations above said battery andto selectively stop at any one of said stations and deliver coal to oneof said ovens, said car including hopper means and at least one coalfeeding duct for feeding coal from said hopper means to any TABLE 2.DUSTCONTENTS Volume of ex- At the inlet At the outlet Volume of ex- At theoutlet hausted wind of of the dust of the prehausted wind of of the dustthe exhauster of General collector cleaner in the coal charging removerin the dust remover efficiency in glm. g./Nm. car in m."/min. gJNm. inNmfi'lmin. in percent August 24. I970 16.8 3.4 500 0.054 1,500 99.0August 28, i970... 17.3 3.7 500 .046 1,500 99.2 August 30. I970 15.6 2.9500 .062 1,500 98.8

When the coal charging car has finished the coal charging operation andthe connector 16 is retreated to be separated from the suction port 19by operating the fluid cylinder 17, the exhauster of the dust collectingapparatus, pre-cleaner and flame of the igniting device in the coalcharging car will be stopped and the car will move to be loaded withcoal for the next charging.

As in the above, as it is impossible from the structure and object of acoal charging car to provide the coal charging car with a giganticapparatus high in the dust collecting and removing efficiency, it hasbeen considered a very difficult problem to completely collect andremove dust at the time of charging with coal. Further, even if a ductis arranged on the oven so as to suck the dust collecting exhaust gas atthe time of charging with coal, the suction ports will be so many thatthe total amount of the leakage will be very large and the suction willnot be effective. However, as shown in the present invention, if thedust collecting system in the coal charging car is provided with anigniting and burning device, the tarry substance and other combustiblecompositions in the dust-containing gas are burned therein and the gasis thus converted to an inert gas, has the dust removed in advance inthe pre-cleaner, is completely introduced and sucked into a plurality ofdivided sub-ducts arranged on the oven, is led into a large dust removerhigh in the performance and fixed on the ground and has dust removedtherein, no dustcontaining gas will leak out around the coal chargingcar, the danger of the explosion of the gas will be perfectly prevented,the brown color of the gas will be eliminated and the dust will be ableto be substantially completely removed. Therefore, the present inventionis very useful to the improvement of the invironment and the preventionof the pollution of the atmosphere.

tion means to an exhaust port on said car,

e. stationary dust-removal means,

f. stationary suction means,

g. stationary duct means communicating with said stationary dust-removaland suction means and extending along the path of said car, said ductmeans including a plurality ofinlet ports, each arranged to join saidexhaust port when said car is located at one of said stations, and

h. valve means at each of said inlet ports arranged to be automaticallyopened by the presence of said car at the corresponding station,

i. whereby the dust laden gas is subjected to initial filtering on saidcar and subsequent more complete filtering after removal from said car.

2. The combination of claim 1 wherein said stationary duct meanscomprises a plurality of sub-ducts arranged end to end along the path ofsaid car and each including at least two of said plurality of inletports, a main duct leading to said stationary dust-removal means, aplurality of connecting ducts each joining a sub-duct to said main duct,a valve in each of said connecting ducts and control means actuated bythe presence of the car at a predetermined station for positivelyopening the valve in the connecting duct leading to the sub-ductcontaining the inlet port associated with said predetermined station andfor positively closing the valve in the other connecting ducts wherebyleakage through the plurality of closed valve means at said inlet portsis minimized.

3. The combination of claim 2 wherein said control means comprises anelectrical switch at each of said stations, relay means, a plurality ofsolenoid operated valves equal to the number of valves in saidconnecting ducts, a piston-cylinder device for operating each of saidconnecting duct valves, and a pressurized fluid system controlled bysaid solenoid activated valves for opening and closing said connectingduct valves.

4. The combination of claim 1 wherein said initial gas filter means onsaid car comprises a rotatably mounted screen through which said dustladen air is collected, water storage means, means for spraying waterfrom said storage means on said screen, and means for storneouslyopening the valve means at the one inlet port.

2. The combination of claim 1 wherein said stationary duct meanscomprises a plurality of sub-ducts arranged end to end along the path ofsaid car and each including at least two of said plurality of inletports, a main duct leading to said stationary dust-removal means, aplurality of connecting ducts each joining a sub-duct to said main duct,a valve in each of said connecting ducts and control means actuated bythe presence of the car at a predetermined station for positivelyopening the valve in the connecting duct leading to the sub-ductcontaining the inlet port associated with said predetermined station andfor positively closing the valve in the other connecting ducts wherebyleakage through the plurality of closed valve means at said inlet portsis minimized.
 3. The combination of claim 2 wherein said control meanscomprises an electrical switch at each of said stations, relay means, aplurality of solenoid operated valves equal to the number of valves insaid connecting ducts, a piston-cylinder device for operating each ofsaid connecting duct valves, and a pressurized fluid system controlledby said solenoid activated valves for opening and closing saidconnectinG duct valves.
 4. The combination of claim 1 wherein saidinitial gas filter means on said car comprises a rotatably mountedscreen through which said dust laden air is collected, water storagemeans, means for spraying water from said storage means on said screen,and means for storing the dirty water from said screen.
 5. Thecombination of claim 1 wherein said exhaust port includes means forconnecting said exhaust port to any one of said inlet ports and meansfor simultaneously opening the valve means at the one inlet port.